2. Dilute hydrochloric acid reacts with zinc to form zinc chloride and hydrogen. (a) Find the volume of dilute hydrochloric acid of concentration 0.25 mol/dm^3 required to
react with 13 g of zinc.

(b) What is the volume of hydrogen formed at r.t.p.?

Step-by-step explanation:

Zn + 2HCl => ZnCl2 + H2

Moles of Zn = 13g / (65.38g/mol) = 0.198mol

Volume of HCl = 0.396mol / (0.25mol/dm³) = 1.58dm³.

Volume of H2 = 0.198mol * (22.4dm³/mol) = 4.43dm³.

The building is approximately 39 m high.

Step-by-step explanation:

As seen in the diagram attached, a triangle can be formed between the boy, the top of the building, and the lateral distance between the boy and the building.

We can now use trigonometric laws to find the distance AC between the boy's head and the top of the building.

tan 40 = AC/37.5

AC = 37.5 X tan 40 = 31.46m

We have just obtained the distance from the boy's head to the building top.

To get the true height of the building, we have to add the height of the platform the boy is standing on to the value just found.

7.5m + 31.46m = 39m